A dechlorination system for 4-chlorotoluene using a two-compartment cell separated by a palladized ion exchange membrane

A new successive dechlorination system was constituted using a two-compartment cell separated by a palladized cation or anion exchange membrane in place of a Pd sheet. 4-Chlorotoluene as a substrate was dechlorinated to toluene in this system, and the rate and current efficiency for the toluene production were greatly improved in methanol with high polarity. Moreover, both of the palladized membranes showed a current efficiency much higher than the palladized Pd sheet as a reference. This could be ascribed to the larger active surface area for the palladized membranes due to the deposition of fine Pd black particles on the membranes and the partial penetration of 4-chlorotoluene molecules in to hydrophilic pores based on the miscibility of methanol with water. The current efficiency depended on the concentration of 4-chlorotoluene and was over 90% at a concentration of 2 M in either palladized membrane.